Die assembly for use in an apparatus for forming a workpiece

ABSTRACT

A die assembly for forming a workpiece includes a support clamp, a first clamp that is movable relative to the support clamp to engage a first portion of the workpiece, and a second clamp that is movable relative to the support clamp to engage a second portion of the workpiece. A forming punch is movable relative to the support clamp after the first clamp and the second clamp have been moved to form the workpiece.

BACKGROUND OF THE INVENTION

This invention relates in general to an apparatus for forming aworkpiece to have a desired shape. In particular, this invention relatesto an improved die assembly for use in such an apparatus for forming aworkpiece that prevents the formed workpiece from being undesirablyretained on the die assembly.

A wide variety of apparatuses are known in the art for formingworkpieces to have a desired shape. For example, mechanical presses arewell known apparatuses that are commonly used to manufacture a widevariety of workpieces including, for example, relatively large orthick-walled workpieces such as side rails, cross members, and othercomponents for vehicle frame assemblies. A typical mechanical pressincludes a stationary portion (typically referred to as a bed) having afirst die section of a die assembly secured thereto, a movable portion(typically referred to as a ram) having a second die section of the dieassembly secured thereto, and an actuating mechanism for selectivelymoving the ram toward and away from the bed. When the ram is movedtoward the bed, the first and second die sections of the die assemblyengage the workpiece and exert forces thereon to mechanically form itinto a desired shape. When the ram is moved away from the bed, the firstand second die sections are moved apart from one another to allow theformed workpiece to be removed and the next workpiece to be formed to beinserted.

It is often desirable to form workpieces to have relatively complexshapes that can include, for example, stiffening features or mountingbosses at various locations. These relatively complex shapes may, afterformation, cause portions of the formed workpiece to be clamped orotherwise retained on portions of the die assembly. Such retention ofthe formed workpiece on the die assembly is usually undesirable becauseit can inhibit the removal of the formed workpiece from the dieassembly, thereby increasing the amount of time and effort necessary tocomplete the forming cycle. Thus, it would be desirable to provide animproved die assembly for use in an apparatus for forming a workpiecethat prevents the formed workpiece from being undesirably retained onthe die assembly.

SUMMARY OF THE INVENTION

This invention relates to an improved die assembly for use in anapparatus for forming a workpiece that prevents the formed workpiecefrom being undesirably retained on the die assembly. The die assemblyincludes a support clamp, a first clamp that is movable relative to thesupport clamp to engage a first portion of the workpiece, and a secondclamp that is movable relative to the support clamp to engage a secondportion of the workpiece. A forming punch is movable relative to thesupport clamp after the first clamp and the second clamp have been movedto form the workpiece.

Various aspects of this invention will become apparent to those skilledin the art from the following detailed description of the preferredembodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view, partially broken away, of a dieassembly in accordance with this invention, together with a workpiece tobe formed.

FIG. 2 is a sectional elevational view taken along 2-2 of FIG. 1 showingthe workpiece initially installed and unclamped on the die assembly.

FIG. 3 is a sectional elevational view taken along 3-3 of FIG. 1 showingthe workpiece initially installed and unclamped on the die assembly.

FIG. 4 is a sectional elevational view similar to FIG. 2 showing theworkpiece partially clamped on the die assembly.

FIG. 5 is a sectional elevational view similar to FIG. 2 showing theworkpiece partially clamped on the die assembly.

FIG. 6 is a sectional elevational view similar to FIG. 4 showing theworkpiece fully clamped on the die assembly.

FIG. 7 is a sectional elevational view similar to FIG. 5 showing theworkpiece fully clamped on the die assembly.

FIG. 8 is a sectional elevational view similar to FIG. 6 showing theworkpiece after being formed on the die assembly.

FIG. 9 is a sectional elevational view similar to FIG. 7 showing theworkpiece after being formed on the die assembly.

FIG. 10 is a perspective view of the die assembly and the workpieceshown in FIGS. 8 and 9.

FIG. 11 is a perspective view of the formed workpiece after removal fromthe die assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, there is illustrated in FIG. 1 a dieassembly, indicated generally at 10, in accordance with this invention.The die assembly 10 is adapted to be supported on any conventionalapparatus for forming a workpiece to have a desired shape, such as amechanical press (not shown) as described above. The illustrated dieassembly 10 includes a base 11 and a first clamp, indicated generally at12. The first clamp 12 includes a rigid clamp 14 and a floater clamp 16.The rigid clamp 14 includes a cavity 18 that engages the floater clamp16 for relative movement therebetween. The floater clamp 16 isresiliently supported within the cavity 18 of the rigid clamp 14. Ifdesired, a resilient support 15 may be disposed between the floaterclamp 16 and the rigid clamp 14, although such is not required. Theresilient support 15 may, for example, be embodied as a fluid springsuch as a conventional nitrogen-charged die spring. The resilientsupport 15 may alternatively be pneumatic or hydraulic in nature (suchas by means of a gas or a liquid provided within the cavity 18) or maybe mechanically operated, such as by means of a helical spring, aBelleville spring, a leaf spring, an elastomeric spring, and the like.The first clamp 12 also includes a second clamp 20 that operates alongwith the first clamp 12 to support a workpiece (such as indicatedgenerally at 22) on portions of the die assembly 10. The operation ofthe first clamp 12 and second clamp 20 will be explained below.

The illustrated workpiece 22 includes a first leg 24 having an unevenprofile or complex geometry that includes a stiffening channel 24a orother protruding feature, boss, fin, rib, or structure. The illustratedworkpiece 22 also includes a second leg 26, which is shown as anextending side from the first leg 24. As will be explained in detailbelow, the second leg 26 will be formed by the die assembly 10 to have adesired shape. The first leg 24 of the illustrated workpiece 22 hasthree locating apertures 28 formed therethrough, although any number ofsuch locating apertures 28 (or none at all, if desired) may be provided.

The illustrated locating apertures 28 are adapted to be engaged byrespective movable pin assemblies 30. Each of the movable pin assemblies30 is supported on and extend beyond an upper surface of a support clamp32. The structure and operation of the support clamp 32 and the movablepin assemblies 30 will be explained below.

The illustrated support clamp 32 is supported on the base 11 for lateralmovement relative thereto for selective engagement with the second leg26 of the workpiece 22. However, the support clamp 32 may be supportedfor any desired movement relative to the base 11. The illustratedsupport clamp 32 includes at least one pin slot 34 that engages themovable pin assembly 30. The illustrated pin slot 34 is an elongatedslot that allows the support clamp 32 to move relative to the movablepin assembly 30. The relative fit between the pin slot 34 and themovable pin assembly 30 provides a sufficient locating tolerance toorient the workpiece 22 within the die assembly 10. The support clamp 32may include a cam follower 36 that cooperates with a cam actuator 38 toeffect the selective movement of the support clamp 32 relative to thebase 11 in the manner described below. Alternatively, the support clamp32 can be moved relative to the base 11 by any desired mechanism. Forexample, the support clamp 32 can be moved relative to the base 11 bymeans of a hydraulically driven ram, a reciprocating rod and clevis, anoscillating actuator, a linear motor, a rack and pinion drive, and thelike.

A forming punch 40 is supported on the base 11 for movement relativethereto. The forming punch 40 may be moved by a cam assembly 42, whichmay be embodied as any device that can move the forming punch 40 inorder to deform the workpiece 22 as desired. The cam assembly 42 may besimilar to the clamping actuator examples mentioned above. The formingpunch 40 includes a leading edge 44 that cooperates with a formingrecess 46 provided in the support clamp 32. The cooperating leading edge44 and the forming recess 46 are moved across the base 11 from an openedposition, shown in FIGS. 6 and 7, to a closed position, shown in FIGS. 8and 9. The closed position creates a cavity 48, shown in FIGS. 8 and 9,that defines the general shape of the second leg 26 to be formed.

Initially, as shown in FIGS. 2 and 3, the die assembly 10 is disposed inthe opened position such that the workpiece 22 can be loaded onto themovable pin assemblies 30. Each of the movable pin assemblies 30includes a pin nose 50 that extends through the locating aperture 28.Each pin nose 50 is supported on an offset arm 52, although such is notrequired. The offset arm 52, or alternatively the pin nose 50 directly,engages a pin actuator 54 by way of an optional push rod 56. The pinactuator 54 may be embodied as any structure that can move the pin nose50 to an extended position to allow the workpiece 22 to be loaded intothe die assembly 10. In a preferred embodiment, the pin actuator 54 is aresilient nitrogen spring that is biased in an extended position. Theextended position of the pin actuator 54 positions the pin nose 50 abovethe upper surface of the support clamp 32. Alternatively, the pinactuator 54 may be a mechanical spring, a hydraulic spring, a magneticspring, or the like. The pin actuator 54 may, alternatively, be ahydraulic, pneumatic, or magnetic powered actuator that is force drivenfrom the retracted position to the extended position, if so desired. Thepin actuator 54 can be either fixed directly to the base 11 or securedto another point relative to the base 11 and allows the pin nose 50 tobe moved to a retracted position (shown in FIGS. 4, 6, and 8) by thefirst clamp 12. The first clamp 12 moves the workpiece 22 against theresilient force of the pin actuator 54. The retracted position of thepin actuator 54 allows the component pre-form 22 to engage the surfaceof the support clamp 32.

In operation, the workpiece 22 is placed in the die assembly 10 byengaging the pin nose 50 through the locating aperture 28, as shown inFIG. 2. The workpiece 22 may initially rest on a portion of the offsetarm 52, though such an orientation is not required. The support clamp 32may also include one or more wear plates 58 (shown in FIGS. 3, 5, and 7)that support the workpiece 22. The wear plates 58 may also be adapted toreduce the coefficient of friction between the workpiece 22 and thesupport clamp 32. As shown in FIGS. 4 and 5, the first clamp 12 clampsthe workpiece 22 onto the support clamp 32. The rigid clamp 14 is shownhaving a pin recess 60 that accepts the pin nose 50, if so provided. Therigid clamp 14 may have more than one pin recess 60 to accommodate theappropriate number of pin noses 50. The floater clamp 16 may also beprovided with one or more pin recesses 60 if so desired. When actuated,the floater clamp 16 contacts the surface of the workpiece 22. In theillustrated embodiment, the floater clamp 16 is configured to contactthe stiffening channel 24a. The floater clamp 16 resiliently reactsagainst the rigid clamp 14 to apply a proportional clamping force ontothe workpiece 22 as the first clamp 12 moves toward the 22. The firstclamp 12 contacts the first leg 24 and engages the pin nose 50 withinthe pin recess 60. The first clamp 12 forces the movable pin assembly 30into the pin slot 34.

As the first clamp 12 is being brought into contact with the first leg24 of the workpiece 22, the support clamp 32 is moved to the closedposition illustrated in FIGS. 5 and 7. In the closed position, thesupport clamp 32 locates against the adjacent surface of the second leg26 of the workpiece 22. The support clamp 32 is moved toward the secondleg 26 of the workpiece 22 by the relative action of the cam follower 36against the cam driver 38. The pin slot 34 moves relative to the movablepin assembly 30 as the support clamp 32 is pushed into the closedposition against a portion of the second leg 26. The second clamp 20moves toward the second leg 26 as the support clamp 32 moves toward theclosed position. The movement of the second clamp 20 is illustrated as alateral movement across the surface of the forming punch 40, though sucha movement direction is not required. Alternatively, the second clamp 20may move in the same direction as the first clamp 12 if so desired. Thesecond clamp 20 and the support clamp 32 engage or otherwise trap andhold the second leg 26 therebetween. The movement of the first clamp 12onto the support clamp 32 is coordinated in time with the movement ofthe second clamp 20 toward the second leg 26. This coordinated movementis such that the workpiece 22 is not subjected to damaging bending ortwisting loads.

Referring now to FIGS. 8 and 9, when the workpiece 22 is trapped betweenthe first clamp 12, the second clamp 20, and the support clamp 32; thecam actuator 38 (if so provided) travels past the cam follower 36 toprovide an additional lock or restraint to movement of the support clamp32 relative to the forming punch 40. The forming punch 40 is then drivenby the second cam assembly 42 into contact with a portion of the secondleg 26. The second cam assembly 42 continues to press the leading edge44 into the portion of the second leg 26. The leading edge 44 folds theportion of the second leg 26 into the forming recess 46 to form a flange62. FIG. 10 illustrates the die assembly 10 in the closed position afterforming the flange 62. FIG. 11 shows a finished workpiece 64 afterejection by the movable pin assemblies 30 from the die assembly 10.

The steps to release the finished part 64 from the die assembly 10 maybe conducted in the reverse order from the clamping steps describedabove, though such is not required. Alternatively, the load applied bythe first clamp 12 may be reduced prior to retracting the leading edge44 from engagement with the forming recess 46. This may reduce the loadrequired to move the leading edge 44 from engagement with the flange 62.Once the leading edge 44 is pulled past the flange 62, the second clamp20 is moved away from the remainder of the second leg 26 of the finishedworkpiece 64. The first clamp 12 is further retracted from contact withthe finished workpiece 64 so that the movable pin assemblies 30 canarticulate from the pin slots 34 and push the finished workpiece 64 outof the die assembly 10. As the movable pin assemblies 30 eject thefinished workpiece 64 from the die assembly 10, automated handlingequipment may be used to move the finished workpiece 64 onto the nextoperation. The cycle is then ready to accept another workpiece 22 andrestart the forming process.

The principle and mode of operation of this invention have beenexplained and illustrated in its preferred embodiment. However, it mustbe understood that this invention may be practiced otherwise than asspecifically explained and illustrated without departing from its spiritor scope.

1. A die assembly for forming a single workpiece comprising: a supportclamp; a first clamp that is movable relative to the support clamp toengage a first portion of a single workpiece; a second clamp that ismovable relative to the support clamp to engage a second portion of thesingle workpiece; and a forming punch that is movable relative to thesupport clamp after the first clamp and the second clamp have been movedto form a flange on the end of the second portion of the singleworkpiece, the flange being folded inward of the single workpiece. 2.The die assembly of claim 1 wherein the support clamp includes a recessthat cooperates with the forming punch to form the single workpiece. 3.The die assembly of claim 1 wherein the support clamp includes a pinslot disposed about a portion of a movable pin assembly, the supportclamp being movable relative to the movable pin assembly.
 4. The dieassembly of claim 1 wherein the support clamp includes a cam followerthat is selectively engaged by a cam driver to move the support clampfrom an opened position to a closed position.
 5. The die assembly ofclaim 1 wherein the support clamp includes a cam follower that isselectively engaged by a cam driver to move the support clamp from anopened position to a closed position and to support the support clampagainst the movement of the forming punch.
 6. The die assembly of claim3 wherein the movable pin assembly is supported on a resilient memberfor biased movement.
 7. The die assembly of claim 6 wherein theresilient member is a nitrogen charged spring.
 8. The die assembly ofclaim 3 wherein the movable pin assembly is located above the supportclamp surface such that the single workpiece does not engage the supportclamp.
 9. The die assembly of claim 1 wherein the first clamp assemblyincludes a resilient member that resiliently supports the floater clampwithin the rigid clamp.
 10. The die assembly of claim 9 wherein theresilient member is a nitrogen charged spring.
 11. A die assembly forforming a feature onto a single component comprising: a base having atleast one movable pin assembly that is biased in an extended position; asupport clamp engaging the base for relative movement therewith; a firstclamp assembly that is movable relative to the support clamp and havinga rigid clamp and a floater clamp, the first clamp assembly furtherhaving a pin recess adapted to engage a portion of the movable pinassembly; a forming punch engaging the base for relative movementtherewith and having a leading edge that cooperates with the supportclamp to form a feature; and a second clamp that is movable relative tothe forming punch, the second clamp cooperating with the support clampto engage a portion of a single component therebetween, wherein thefeature is a flange on the end of the portion of the single component,the flange being folded inward of the single component.
 12. The dieassembly of claim 11 wherein the support clamp includes a recess thatcooperates with the forming punch to form the single component.
 13. Thedie assembly of claim 11 wherein the support clamp includes a pin slotdisposed about a portion of the movable pin assembly, the support clampbeing movable relative to the movable pin assembly.
 14. The die assemblyof claim 11 wherein the support clamp includes a cam follower that isselectively engaged by a cam driver to move the support clamp from anopened position to a closed position.
 15. The die assembly of claim 11wherein the support clamp includes a cam follower that is selectivelyengaged by a earn driver to move the support clamp from an openedposition to a closed position and to support the support clamp againstthe movement of the forming punch.
 16. The die assembly of claim 11wherein the movable pin assembly is supported on a resilient member forbiased movement.
 17. The die assembly of claim 16 wherein the resilientmember is a nitrogen charged spring.
 18. The die assembly of claim 11wherein the movable pin assembly is located above the support clampsurface such that the single component does not engage the supportclamp.
 19. The die assembly of claim 11 wherein the first clamp assemblyincludes a resilient member that resiliently supports the floater clampwithin the rigid clamp.
 20. The die assembly of claim 19 wherein theresilient member is a nitrogen charged spring.
 21. A die assembly forforming a flange onto a single workpiece comprising: a base having atleast one movable pin assembly biased in an extended vertical position;a support clamp engaging the base for relative horizontal movementtherewith; a first clamp assembly vertically movable relative to thesupport clamp and having a rigid clamp, a floater clamp, and a pinrecess adapted to engage a pin nose of the vertically movable pinassembly; a forming punch engaging the base for relative horizontalmovement therewith and having a leading edge; and a second clamphorizontally movable relative to the forming punch, the second clampcooperating with the support clamp to engage a portion of a singleworkpiece therebetween and the leading edge cooperating with the supportclamp to form a flange on the end of the single workpiece portion. 22.The die assembly of claim 21, wherein the flange is folded inward of thesingle workpiece.